1. Technical Field
The present disclosure relates to a movement device having a Stewart platform, in particular, to a movement device having a Stewart platform with four extensible links.
2. Description of Related Art
Stewart platform has been used in many applications, for example flight simulators, machine tools, biped locomotion system and surgery manipulators. The geometry of conventional Stewart platform is composed of a fixed base, a movable platform, and six linear actuators connecting the fixed base and the movable platform. This is a six degree of freedom universal-prismatic-spherical mechanism, including heave, surge, sway, yaw, pitch, and roll. No additional structural members are needed in Stewart platform because the actuators also function as structural members. The drawbacks of the Stewart platform are small workspace and complexity in control. In addition to controlling six linear actuators simultaneously in a nonlinear manner, the existence of singular positions creates more complexity in controlling the mechanism.